Gear-operated machine wrench for propeller blade nuts



E. T. ABLE July 5, 1955 GEAR-OPERATED MACHINE WRENCH FOR PROPELLER BLADE NUTS 3 Sheets-Sheet 1 Filed Feb. 2, 1955 INVENTOR. [kW/Wm 7,7454:

July 5, 1955 E. T. ABLE 2,712,255

GEAR-OPERATED MACHINE WRENCH FOR PROPELLER BLADE NUTS Filed Feb. 2, 1953 5 Sheets-Sheet 2 IN V EN TOR.

y 5, 1955 E. T. ABLE 2,712,255

GEAR-OPERATED MACHINE WRENCH FOR PROPELLER BLADE NUTS Filed Feb. 2, 1953 3 Sheets-Sheet 3 IN V EN TOR.

fan 4R0 7. 4%:

United States Patent GEAR-OPERATED MACHINE WRENCH FOR PROPELLER BLADE NUTS Edward T. Able, Denver, Colo., assignor to B. K. Sweeney Mfg. Co., Denver, Colo., a corporation 01: Colorado Application February 2, 1953., Serial No. 334,397 10 Claims. (C 81- -57);

This invention relates to a gear-operated machine wrench device more particularly designed for installing and removing airplane propeller blades in and from propeller hubs. The blades, in the usual airplane propeller, are held in place in radially positioned blade sockets on a unitary propeller hub by means of castellated ring nuts which surround the stems of the blades and which are threaded into the open extremities of the blade sockets. These ring nuts must be tightened uniformly throughout the entire series of blades to properly distribute the stresses and strains throughout. the hub. They also must be tightened with such exceedingly great pressure that the use of ordinary spanner wrenches is impractical.

The principal object of this invention is to provide a propeller blade wrench device which will easily and efiiciently tighten the blade ring nuts of a propeller hub to a uniform predetermined tightness throughout the entire series of blades.

Another object of the invention resides in the combination with a ring nut actuating means, of means which will exert a pulling action on the propeller blades to simultaneously withdraw the blades from the hub sockets as the ring nuts are loosened.

A further object is to so construct the device that very little manual exertion will be required to exert an exceedingly great tightening action on the propeller blade ring nuts, and so that the device will, be applicable to propellers of various makes, sizes and various numbers of propeller blades.

Other objects and, advantages reside in the detail construction of the invention, which, is designed for simplicity, economy, and efliciency. These will become more apparent from the following description.

In the following detailed description of the invention reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

Fig. 1 is a side view of the improved wrench device for propeller blade nuts, illustrating the position of various parts of a conventional aircraft propeller in broken line;

Fig. 2 is a horizontal section, taken on the line 2-2, Fig. 1;

Fig. 3 is a vertical section, taken on the line 3 3, Fig. l;

Fig. 4 is a top view of the improved wrench device;

Fig. 5 is a detail section through a split sprocket and spacing sleeve employed in the invention, the section being taken on the line 55, Fig. 3; and

Fig. 6 is a detail section through a transmission gear train unit employed in the improved wrench device, taken on the line 6-6, Fig. 4.

in Fig. l, a typical four-bladed aircraft propeller is illustrated in broken lines The propeller is indicated as though dismounted and supported in a horizontal "ice position. The hub of the propeller is indicated at 10.-

castellated blade ring nuts 16. This wrench'devic'e is designed for attachment to the hood base 13 and acts to rotate the blade ring nuts 16.

The wrench device is mounted upon a base plate 17 of a diameter to exceed the diameter of the largest expected hood base 13. The base plate is provided with a plurality of cap screw openings 18 positioned to align with the cap screw openings in the base 13 and adapted to receive the cap screws 14 which are usually employed for holding the streamlined hood in place on the propeller.

The base plate 17 is provided with an axially positioned, internally threaded post sleeve 19 which extends above and below the base plate 17. A circular, shoulder portion 20 surrounds the sleeve 19 above the plate 17. The shoulder portion 20 is provided with a circular series (preferably twelve) of equally spaced guide pin sockets 21.

A cylindrical supporting post 22 is supported in the sleeve 19. The lower extremity of the post 22 is threaded, as indicated at 23, to engage the internalthreads of the sleeve 19 so that rotation of the. post will cause it to move upwardly and downwardly in the sleeve 19 The post 22 is provided with a fixed cap 46 having a central non-circular wrench opening 47 for receiving the wrench stud of any suitable wrench, by means of which the post may be rotated, and the post is provided with an enlarged shoulder portion 24 intermediate its length. A wrench frame casting 25 surrounds the post 22 and is supported thereon by the enlarged shoulder portion 24. The. casting 25 is rotatable about the post 22 and can beset in any desired circumferential position thereabout by means of vertical guide pins 26 which are fixedly mounted in the casting 25 and extend down wardly therefrom to engage in the guide pin sockets 21. There are preferably a pair of the guide pins 26 at each side of the casting 25, one pin in each pair being aligned on a common diameter with one pin of the opposite pair, and the remaining pin of each pair. being spaced rearwardly from the first pins so as to correspond to the spacing of the guide pin sockets 21.

The casting 25 is provided with suitable supporting arms 27, each of which carries a stud-receiving socket 28 provided with a set screw 35. The arms 27, the sockets 28 and the setscrews are for the purpose of supporting and securing a transmisson gear casing 29 on the casting 25. The gear casing 29Tcontains a drive gear 4 9 and a driven gear 50. A compound gear is mounted on a countershaft 51 between the gears 49 and 50. The compound gear is formed as a unit with a relatively large intermediate gear 52 in mesh with the drive gear 49, and'a relatively small intermediate gear 53. in mesh with the driven gear 50. Thus, it can be seen, with reference to Fig. 6, that a multiplication of torque is obtained between the drive gear 49 and-the driven gear 50. The driven, gear is provided with an annular hub. provided with internal splines 54, and: the drive gear 49 is fixedly mounted on a power input shaft 30 having a non-circular axial socket for receiving the actuating stud ofany suitable actuating wrench.

An adapter device 31 is inserted in the socket 55'. of the power. input shaft 30, andv a conventional ratchettorque wrench 32 is applied to'the adapter device'31' so that the power input shaft 30 can be rotated by the torque wrench 32 to any desired degree of tortional resistance. The torque wrench may be of any of the standard varieties of ratchet torque wrenches at present on the market.

The transmission gear casing 29 is provided with stud bosses 33 from the extremity of each of which a stud 34 projects. The studs 34 are inserted into the studreceiving sockets 28 and locked therein by means of the set screws 35. A splined sleeve 36, carrying an integral drive sprocket 37, is inserted in the annular hub of the driven gear 50, so that when the torque wrench 32 is rotated about the axis of the power input shaft 30, the drive sprocket 37 will be rotated with a multiplied torque effect.

Power is transmitted to the blade ring nuts 16 from the drive sprocket 37 through the medium of an endless power transmission chain 38 and an annular driven sprocket 39. The driven sprocket 39 is split in two halves and has an internal diameter sufiicient to surround the stem of the propeller blade. The two halves are secured together in any desired manner, such as by means of suitable connecting screws 40. The split sprockets are formed in a plurality of different designs to accommodate and interfit with the various types. of ring nuts and blades encountered on conventional propellers, but in all cases they will be split so that they may be readily placed about the propeller blades 15, and they will be provided with suitable projecting lugs 41 adapted to enter the interstices between the castellations in the castellated ring nuts to transmit torque to the latter.

The split driven sprocket is urged against the ring nut to maintain the lugs 41 in place therein by means of a split spacer ring 42 which is adapted to surround the propeller blade and bear against the outer face of the split sprocket. The spacer rings 42 are designed to meet the conditions encountered on various propellers, but in all cases they will have an abutment surface which will rest against an encircling rib or flange 48 which is usually formed on the conventional propeller blades to facilitate withdrawal of the blade from the hub. The spacing ring is positioned between the split driven sprocket 39 and the propeller rib or flange 48 so as to transmit longitudinal movement from the ring nut 16 to the propeller blade to withdraw the latter from its hub socket 11. The spacer ring 42 is preferably formed in two halves hinged together at one side by means of a suitable hinge 45 and provided at the other side with a suitable clamping bolt 44 so that it may be quickly and easily placed in position on the blade.

Let us assume that it is desired to remove the blades from a four-bladed airplane propeller as illustrated in Fig. l. The hub hood is removed from the propeller. The base plate 17 is bolted to the hood base 13 by the conventional cap screws 14. The split driven sprocket 39 is positioned around one of the propeller blades and forced into engagement with the castellations on the propeller blade ring nut 16. The two halves are then clamped together by means of the connecting screws 46. The split spacer ring 42 is now opened and placed around the propeller blade, between the split sprocket 39 and the withdrawal flange 48 on the propeller blade, and closed and locked by means of the clamping bolt 44.

The casting 25 is now lifted and rotated to position the drive sprocket 37 over the driven sprocket 39, and is then lowered to cause the guide pins 26 to enter their respective receiving sockets 21. The transmission chain 38 is now placed about both sprockets and the post 22 is rotated to thread it upwardly so as to raise the casting 25 and tighten the chain 38.

' The torque wrench 32 is now actuated back and forth to rotate the drive sprocket 37 and cause the chain 38 to rotate the split driven sprocket 39. This, in turn, will rotate the blade ring nut 16 to unscrew the latter from its blade-receiving socket 11. As the nut 16 moves outwardly, it will force the spacer ring 42 outwardly against the flange 48 on the propeller blade to simultaneously loosen and withdraw the latter from the hub as the retaining ring nut is unscrewed.

The split sprocket and split ring are now removed. The casting 25 is lifted sufficiently to release the pins 26 and rotated- (3 pin spaces) to allow the pins 26 to engage a new set of pin sockets 21. This positions the drive sprocket 37 in proper position for removal of the second blade. This procedure is continued throughout the entire four blades, and to replace the blades the procedure is simply reversed and the torque wrench 32 is employed to tighten the nuts 16 to a uniform tightness, as indicated by the conventional torque indicating mechanism on the torque wrench 32.

For three-bladed propellers, the casting 25 is shifted in intervals of four pin spaces in the shoulder portion 20 or per shift.

While a specific form of the improvement has been described and illustrated herein, it is to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

l. A wrench device for rotating propeller blade ring nuts in the hub of an airplane propeller, comprising: a base member adapted to be axially mounted on said hub; 21 frame member; means for supporting said frame member in adjustable spaced relation on said base member; a first power transmission device mounted on said frame member; a driving means mounted on and rotatable by said first power transmission device; a driven ,.means adapted to surround a blade of said propeller; a second power transmission device transmitting torque from said driving means to said driven means; a means on said driven means adapted to engage the ring nut of the latter propeller blade; and means for actuating said power wrench.

2. A device for rotating propeller blade ring nuts as set forth in claim 1 having means for locking said frame member in preset positions about the axis of said propeller.

3. A device for rotating propeller blade ring nuts as set forth in claim 2 having a spacing device adapted to surround the blade of the propeller and transmit axial movement from said driven means to said blade to move the latter longitudinally.

4. A device for rotating propeller blade ring nuts a set forth in claim 3 in which the means for actuating said power wrench comprises a torque wrench operatively connected to said first power transmission device for actuating the latter.

5. A wrench device for rotating propeller blade ring nuts in the hub of an airplane propeller, comprising: a base member adapted to be axially mounted on said hub; a frame member; means for supporting said frame member in adjustable spaced relation on said base member; a power transmission device mounted on said frame member; a chain sprocket mounted on and rotatable by said power transmission device; a second chain sprocket adapted to surround a blade of said propeller; an endless transmission chain surrounding both said sprockets; means on said second sprocket adapted to engage the ring nut of the latter blade; and means for actuating said power transmission device.

6. A device for rotating propeller blade ring nuts as set forth in claim 5 having means for urging said frame member away from said base member to increase the tension in said chain.

7. A device for rotating propeller blade ring nuts comprising: a base member having an annular series of guide pin sockets; means for securing said base member on a propeller hub; a threaded socket formed in said base member and adapted to axially align with the axis of said propeller hub; a supporting post threaded into said threaded socket in alignment with the axis of the latter; a frame surrounding said post; supporting means on said post rotatably supporting said frame thereon; guide pins projecting from said frame into said guide pin sockets; a geared power transmission device supported by said frame; a chain sprocket mounted on said power transmission device; an input shaft in said power transmission device arranged when actuated to rotate said sprocket; an actuating wrench mounted on said input shaft for rotating the latter; and means for transmitting the rotation of said sprocket to a ring nut on a blade of said propeller.

8. A device for actuating propeller blade ring nuts as set forth in claim 7 in which the means for transmitting the rotation of said sprocket to a ring nut comprises a second sprocket adapted to surround a blade of said propeller; means on said second sprocket engaging the ring nut of said latter blade; and an endless transmission chain connecting said two sprockets and transmitting rotation from the first to the second sprockets.

9. A device for actuating propeller blade ring nuts in the hub of an airplane propeller as set forth in claim 8, said second sprocket being split to enable it to be positioned about said blade; and means for connecting the two halves of said split sprocket about said blade.

10. A device for actuating propeller blade ring nuts in the hub of an airplane propeller as set forth in claim 9 having a split spacing sleeve adapted to'surround said blade in contact with said second sprocket; and means for preventing longitudinal movement of said spacing sleeve along said blade.

References Cited in the file of this patent UNITED STATES PATENTS 

